Patent document DE 10 2009 046 339 A1 discusses a hydraulic braking system in a vehicle, which has two brake circuits for supplying hydraulic brake fluid to wheel brake devices, the brake circuits being connected to one shared brake master cylinder that is actuated by the driver, via a hydraulic brake booster, by way of the brake pedal. Located in each brake circuit is a delivery pump that is a constituent of an antilock braking system or electronic stability program by way of which an automatic intervention in the braking system can be carried out.
The antilock braking system or electronic stability program requires wheel rotation speed information that is ascertained by wheel rotation speed sensors, so that the brake pressure in the braking system can be manipulated as desired. In the event of a failure of the control unit of the antilock braking system or electronic stability program, the braking function by way of driver actuation is retained, but the automatic braking intervention that is required for autonomous driving is not guaranteed.